Spark-plug for explosive-engines.



No.7.,868y404.

PATENTE) OCT. 15, 199?.

F, Wl BRADY.

SPARK PLUG FR EXPLQSIVE ENGEES.

PPLIATION FILED MAY ll, 190?.

STATES PATENT oEEroE.v A1

-EEANCIS W. BRADY, or ENGLEWOOD, NEW JERSEY.

spank-PLUG' son ExPLosIVE-ENGINES.

Speciiicaton of Letters Patent.

Patented oct.1 15, '1967,

App1icasofs1eafiny 11. isos. serial' No." siaszziy --Beit known-tirati,FssNcIs W. BRADY, a citizen of full, clear, and enact'description oi theinventomsuch as willl enable. others skilled in the art to which itapperto make and use the same. v l

f .jfiMy invention-relates to improvements in spark .plugs ior oil andga's engines, Vand is designed to provide a ,ignitionsparh and a simpleand .durable 'construction, cheap of manufacture, and readily lkept inserviceable v the two views I v Referring to the drawing, a is a casingof brass or other .f j. the movable terminal c.' The stationary terminalb is bent over at its inner end and carries ne'ar the extremity ofthebent over portion a contact 'n of platinum or other v:

highly efficient insulation of the parts, reliability 4of the condition.

K A preferred form of' y improved spark-plug is illus- Atratedin theaccompanying drawing, wherein, v

` Figui-el isa.- plan view, and, 2 is a. sectionalview g,

throughthe central axial line of Fig. 1.

letters of reference indicate similar parts in suitable metal supportingthe stationary terminalb and suitable material. and it is urthe providedwith a shoulder ii and a stem terminating in ascrew-thre'adedv portion eand a vcontact-clip f. The stem passes through an enlarged cylindricalchamber g in the casing a, and:

' is supported out of contact with the sides of said chamby means oi the'nut j, the partsv are securely clamped.Y

ber bythe insulating Washers and t. The-shoulder d lbears against. theinsulating washer z', which is prefen. ably set into the end of thecasing a so as to be flush with the surface thereof. The stem of theterminal b' passes through the center of the said washers h and 'L' and-The washer may be made of lava. or any other suitableinsulatingmaterial, but I preier to make thel lwasher i of the improvedconstruction illustrated,ior the pnrppse of reducing theescape of oil orgases from lthecylinde;` oi the engine into the chamber g, and at thesame time to preserve the refractory character of thewasher madenecessary because of its relation to the interior of the enginecylinder.` Accordingly, the

l Washer i, as illustrated, is composed of layers of suitable 'I up ofthe screw y'.

highly' refractory insulating materiahpreferably mica, in which astieing plate w, preferably'oi steel, is einbedded, thus giving it therequisite stability to resist the crushing strainsimposed upon itby th'etightening V i'lhe movable terminal c passesV throuzgh a cylindricalopening in the casing a, into which it its'snugly'. The

said movable terminal is provided at its z-inr'rer 'end with a contact moil/platinum orthe like, and at its outer end, v' with a. cap k aving arecess surroundingrthe outer end of the retractile spring Z, whose otherendbears against l a washer r a'recessof the casing L z.v This washer rand the packing s in therecess act as astufiingbpx for the terminal ci.'.Itwill be understood-that in the operation of the e 'gine the contactmoved toward the contact 'n bythe action of timing mechanismsuch as therock- .th'at on the backward swing of the lever, the retractile spring lserves lfor the purposeofstriking the ignition spark. -The terminal c,may,v .when the engine is at `rest, be-pushed inwardly by` hand,soastbring the two vcontacts 111,11., together', and may then berotated,

so as to clean and brighten thecontact surfaces.

v For draining -of any oil which be forced' into or condense within thechamber g, from the engine cylinder past the mica washers', provide theoutlet passage 2' extending through theca'sing a, and in order that themovable .terminal c, whichi's directly the line oi this outlet, may notstop the same, I cutaway the said terminal, as shown, for a' sufficient'distance to leave the outlet passage open in any posit/ionfofthetermnal c.' When the plug is set into the engine' cylinderthe passagewill, of course, communicate with a passage leading outwardlythrough thewall ofthe cylinder.

' The current is led the terminal Ig through the binding -post z, whichis supportedv by the insulating mateing L'ver't, .cushioned by thespringp (if need be) andl l rial y, on the casing a, and the switch qwhich may.

be thrown into and outof. engagement with the clip f,

' thus providinga convenient m'eans for opening the circuit of the sparkplug, or of cutting out' one spafrk plug oi afnurnber supplied 'bythe`same current conductor.

In Vthe above description, read in connection with the accompanyingdrawing, I' have explained the manner -in'which I prefer to constructmyimproved spark plug,

but I do not wish it to be understoodthatmy invention is capable oiembodiment.inQthat-speciiicform alone, since it is evident-'that'..manymay be, made therein Without departing Iroin'the spirit o my invention,which Ihave endeavored to incorporate 1n .the iollowng claims. I

Having thus described my invention, what I claini 1. A :spark-plug forexplosive engines, piovidedj with a stationary electrode, the stem ofthe stationary electrode 4being: supported inv insulating bearings andbeing surrounded intermediate of s'aid bearings with an air-insulti.tion .space communicating with draining passages; sub4 stantially :lsdescribed.

'2. A spariti-plug for explosive engines, provided with-a stationaryelectrode and a movable electrode, tliestem ot the stationary electrodebeing supported in insulating bearings and being surrounded intermediateof s ald bearingswith an air-insulation space communicatingwith drainingpassages, and the vstem of the movable eleetrloe being of reduceddiameter for a portion of its length; said reduced portion 4being.;interposed in the pathrof the drainingpassages; substantially asdescribed.

In testimony whereof I 'affix my signature, in presence

